The present invention relates to a network communication system comprising: a plurality of internal units; a plurality of internal LANs mutually connecting the internal units, the internal LANs being assigned different IP addresses; and a plurality of control units being respectively connected to the internal LANs.
A monitoring unit or a monitoring system, which is capable of monitoring a status of the system, is employed in a storage system having a plurality of storage units, e.g., magnetic disk units, such as a RAID system.
Japanese Patent Gazette No. 8-305501 discloses a monitoring unit and a monitoring system, which monitors a status of a disk array apparatus (large-capacity external storage unit) by inputting status data, which are outputted from a printer interface of the disk array apparatus, to the monitor unit (computer).
Another conventional monitoring system, which monitors a status of a storage system, will be explained with reference to FIGS. 5 and 6.
FIG. 5 is a block diagram showing a structure for data access of a RAID system, which acts as a storage system. The RAID system 80 comprises: a plurality of drive enclosures (DE) 90, each of which has a magnetic disk unit (storage unit) 94; and a plurality of centralized modules (CM) 92, each of which is capable of accessing the magnetic disk units 94 of the drive enclosures 90 via fiber channel interfaces.
The centralized modules 92 of the RAID system 80 are connected to a server computer S via fiber channel interfaces. The server computer S is capable of accessing the magnetic disk units 94 of the drive enclosures 90 via the centralized modules 92.
Note that, in the monitoring system, the units included in the RAID system 80, e.g., the magnetic disk units 94, the drive enclosures 90, the centralized modules 92, are called “internal units”.
FIG. 6 is a block diagram showing a structure for monitoring the drive enclosures 90 and the centralized modules 92 of the RAID system 80. The RAID system 80 includes two monitoring units 96 and 97, each of the monitoring units 96 and 97 is connected to the internal units (the drive enclosures 90 and the centralized modules 92) via independent serial lines. Note that, the serial lines connected to the monitoring unit 96 are shown by solid lines; the serial lines connected to the monitoring unit 97 are shown by dotted lines.
Drive enclosure (DE) monitoring units 98, which manage statuses of the magnetic disk units 94 of the drive enclosures 90, are respectively provided in the drive enclosures 90.
A network port, which can be connected to an external network N, e.g., corporate LAN, is provided to each of the centralized modules 92.
The monitoring units 96 and 97 respectively monitor detected values of voltage sensors, temperature sensors, etc. (not shown), which are provided to the magnetic disk units 94 of the drive enclosures 90 and the centralized modules 92, via the serial lines. When abnormal values, e.g., values greater than threshold values, are detected, the monitoring units 96 and 97 notify the abnormal state to an assigned management computer, which is connected to the external network N, via the centralized modules 92 and the external network N. Further, when the abnormal state is detected, the monitoring unit 96 or 97 sends a command to the internal unit, in which the abnormal state occurs, so as to, for example, urgently turn off a power source of the faulty internal unit.
Even if no abnormal state occurs, the monitoring system sends statuses of the sensors, which are monitored by the monitoring units 96 and 97, to the management computer.
The monitoring units 96 and 97 are connected to multiple (double) networks of the monitor serial lines. With this structure, even if failure is occur in one of the monitoring units or the monitor serial lines connected thereto and a process and communication relating to the monitor cannot be performed, the process and the communication can be performed by the other monitoring unit and the monitor serial lines connected thereto.
To improve performance and reliability of the storage system, e.g., RAID system, redundancy between the system and the sever computer is increased by increasing number of the centralized modules or paths therebetween. Further, the monitoring units monitor not only the centralized modules and the drive enclosures (the storage units) but also other internal units of the storage units, e.g., bus switches of the centralized modules, bus switches between the magnetic disk units included in the drive enclosures.
However, each of the conventional monitoring units serial-communicates with each of the internal units one-on-one. Therefore, if the internal units to be monitored, e.g., centralized modules, bus switches, are increased, the monitoring serial lines and the serial ports of the monitoring units, which corresponds to the monitoring serial lines, must be increased, so that a production cost must be increased.
With increasing number of the internal units to be monitored and a processing speed of the computer, increasing processing speeds of the monitoring units are also required.
However, the conventional monitoring units of the storage system monitor by the serial communication, so it is difficult to increase communication speeds. If the communication speeds are increased, a production cost and a development cost must be increased.